Tripoli residents have been promised food, fuel and medical supplies as rebel forces fought their way towards Colonel Gaddafi's hometown of Sirte.

The National Transitional Council (NTC) said on Saturday that it intended to start bringing in supplies to the Libyan capital over the next few days.

"We have 30,000 tonnes of gasoline," a spokesman said. "We'll start to distribute it to the public starting today. We have diesel fuel (which) will be arriving tomorrow, to support the electricity (power stations)."

He added: "Also, we are going to provide within two days the gas for cooking. And we are working hard to reactivate Zawiya refinery."

The rebels claimed to have seized control of the Ras Ajdir border crossing with Tunisia, which they said would allow them to bring in much needed supplies to Tripoli.

The British government has also pledged £3 million in aid to be channeled through The International Committee of the Red Cross (ICRC). The money is intended to help provide medical expertise as well as food for civilians caught in the fighting.

British International Development Secretary Andrew Mitchell said as the conflict moves into its final stages there were many Libyans in need of urgent humanitarian help.

He said: "The situation on the ground in Tripoli is an incredibly difficult one for humanitarian agencies. But organisations such as the ICRC are doing extraordinary work in dangerous and difficult circumstances to get supplies and doctors through to those in need. This new funding from our development budget will help them to continue their vital work in critical areas across Libya.

"Today we pay a huge tribute to the humanitarian agencies who are risking their lives in Libya to help and sustain their fellow human beings."

Steven Anderson, a spokesman for the ICRC, said: "Medical supplies are one of the main problems that will help people on the ground out there.

"Many drugs are lacking and the import has been slowed down. Even drugs for cancer, diabetes, kidney failure are running out and that is a real issue."

Sky News has reported the discovery of a mass grave in Tripoli, believed to contain the charred remains of around 53 people. Locals said the believed pro-Gaddafi forces to be responsible for the massacre.

On Friday reports emerged of grim scenes at Abu Salim hospital in the capital where decomposing bodies had been abandoned.

And Amnesty International uncovered evidence of the killing of prisoners by pro-Gaddafi forces. The human rights watchdog cited eye witness accounts of soldiers loyal to the regime using grenades and guns to kill captives.

Meanwhile rebel forces moved closer Colonel Gaddafi's hometown of Sirte to the east of Tripoli, after they captured the town of Bin Jawad.

Rebel leaders have said they have been reaching out to the people of Sirte to encourage them to join the new government of Libya. But it is expected that they will face a fierce battle to wrest control of the town from Gaddafi loyalists.